CN107615158A - Optical devices - Google Patents

Abstract

The optical device of the present invention prevents cracks from forming in the window glass plate provided in the housing component. The window glass plate (15) of the optical device (1) is fixed to the cover component (16) by a solder layer (17) between the metal-plated film (15d) and the cover component (16). The end edge of the cover component (16) on the side near the window (16a) has a protrusion (16c2) that protrudes further toward the center of the window (16a) than the end edge on the inner periphery side of the metal-plated film (15d).

Description

optical device

technical field

The present invention relates to an optical device including an optical element inside a casing and a glass member fixed to a window portion of the casing.

Background technique

Conventionally, in an optical device including an optical element inside a casing, a window portion serving as an opening is formed in the casing, and light (optical signal) is incident from the outside through the window portion to an optical device disposed inside the casing. element. Therefore, the above-mentioned window portion is closed by a light-transmitting glass member.

In the optical device described in Patent Document 1, a variable wavelength interference filter is provided as an optical element inside the housing. In this optical device, a cover is provided on the upper portion of the case, and a glass member is bonded to the cover by a fixing member. A window portion consisting of a circular opening is formed at the center portion of the cover, and the glass member is provided so as to close the window portion. The fixing member between the cover and the glass member is made of, for example, low-melting glass, and has the same width as the overlapping width of the cover and the glass member. That is, the inner peripheral edge of the fixing member along the window corresponds to the inner peripheral edge of the cover, and the outer peripheral edge corresponds to the outer peripheral edge of the glass member.

Furthermore, in the optical device (optical switch module) described in Patent Document 2, a MEMS (Micro Electro Mechnical System) micromirror array chip is provided as an optical element inside the housing. In this optical device, a cover frame is provided on the upper portion of the case, and a glass member (plate-shaped sapphire) is bonded to the cover frame by a fixing member. In the cover frame, a window portion including a rectangular opening is formed at the center thereof, and the glass member is provided so as to close the opening. The fixing member between the cover frame and the glass member is formed to have a width narrower than the overlapping width of the cover frame and the glass member, and the inner peripheral edge portion along the opening of the fixing member and the inner peripheral edge portion of the cover frame unanimous.

Patent document 1: Japanese laid-open patent publication "Japanese Patent Laid-Open No. 2015-31903 (published on February 16, 2015)"

Patent document 2: Japanese laid-open patent publication "Japanese Patent Laid-Open No. 2011-8105 (published on January 13, 2011)"

10 is a perspective view showing an example of the main part of the optical device 101. The optical device 101 is equipped with an optical element inside, and a window portion 111a as an opening is formed in the frame 111 constituting the casing, and the window portion 111a is closed by the window portion. The glass plate 112 is blocked. (a) in FIG. 11 is a sectional view taken along the line D-D in FIG. 10 . (b) in FIG. 11 is a cross-sectional view showing a state where a crack has occurred in the glass member shown in (a) in FIG. 11 . (c) in FIG. 11 is a plan view of a part shown in (b) in FIG. 11 . In addition, in this example, the window glass plate 112 is installed in the frame 111 so as to block the window 111 a from below.

In the structure in which the window portion 111a of the frame 111 is closed with the window glass plate 112, soldering is often used as a fixing member for fixing the window glass plate 112 to the window portion 111a of the metal frame 111. Material (Au-Sn). Specifically, as shown in (a) of FIG. 11 , in the area where the solder layer (fixing member) 113 of the peripheral portion of the window glass plate 112 is provided, the metallized film 114 is formed in a ring shape, A solder layer 113 is provided thereon. Therefore, the window glass plate 112 is fixed to the frame 111 by using the solder layer 113 between the metallized film 114 and the frame 111, that is, the solder layer 113 is metallically bonded to the metallized film 114 and the frame 111. .

In this case, the molten solder layer 113 wets and spreads over the entire upper surface of the metallized film 114 . Therefore, if the inner peripheral side edge portion 114a of the metallized film 114 protrudes toward the center side of the window portion 111a than the window portion side edge portion 111b of the frame 111, the molten solder in the solder layer 113 will When the solder is cooled and solidified, due to the difference in thermal expansion coefficient between the solder material of the solder layer 113 and the window glass plate 112, as shown in (b) in FIG. A crack 112a is generated in it. Or after the molten solder of the solder layer 113 is cooled and solidified, due to the difference in thermal expansion coefficient between the solder of the solder layer 113 and the window glass plate 112, the thermal expansion of the window glass plate Strain is generated in the window glass plate 112, and a crack 112a is generated in the window glass plate 112 due to the strain. In this case, the airtightness and durability of the optical device 101 decrease.

That is, when the solder layer 113 is cooled and solidified, the solder layer 113 shrinks. On the solder layer 113 , the shrinkage of the solder cannot be slowed down by the frame 111 in a region where the frame 111 does not exist, so the shrinkage becomes conspicuous. Therefore, in the region where the frame 111 does not exist on the solder layer 113, the shrinkage of the solder layer 113 causes a shock to the metallized film 114, that is, the window glass plate 112 on which the metallized film 114 is formed. Tensile stress toward the outer peripheral end of the metallized film 114 . As a result, cracks 112 a are generated in the window glass plate 112 .

In addition, the inner peripheral edge portion 113a of the solder layer 113 protrudes toward the center of the window portion 111a more easily than the inner peripheral edge portion 114a of the metallized film 114, so the opening area of the window portion 111a becomes narrower.

Here, in the structures described in Patent Documents 1 and 2, the glass member is fixed to the frame by a fixing member provided between the frame (cover or cover frame) constituting the housing and the glass member, and the inner periphery of the fixing member is The side edge portion (corresponding to the above-mentioned inner peripheral side edge portion 114 a ) coincides with the window portion side edge portion (corresponding to the above-mentioned window portion side edge portion 111 b ) of the frame. In such a configuration, due to manufacturing tolerances, the inner peripheral edge of the fixing member tends to protrude toward the center of the window than the inner peripheral edge of the frame along the window. That is, in the structures described in Patent Documents 1 and 2, when solder and a metallized film are used as fixing members, they are the same as the structures shown in (a) and (b) in FIG. 11 As a result, the inner peripheral edge of the metallized film protrudes toward the center of the window than the edge of the frame on the window side, and similarly, cracks occur in the window glass plate.

Therefore, it is an object of the present invention to provide a device capable of preventing cracks from occurring in glass parts by utilizing the difference in coefficient of thermal expansion between the glass parts that close the window of the frame and the solder that fixes the glass parts to the frame. The optical device of the case.

Contents of the invention

In order to solve the above-mentioned problems, the optical device of the present invention includes: a casing member having an opening window; an optical element provided inside the casing member, and light is incident on the optical element through the window; and a window. A glass plate is provided in such a manner as to close the above-mentioned window, and the above-mentioned optical device is characterized in that the above-mentioned window glass plate has a light-transmitting base material and a metal-clad film, and the metal-clad film is formed on the above-mentioned window with a predetermined width. In the outer peripheral portion of the light-transmitting base material, the window glass plate is fixed to the housing member by a solder layer provided between the metallized film and the housing member, and the The edge portion on the side of the window portion has a protruding portion protruding toward the center of the window portion than the edge portion on the inner peripheral side of the metallized film.

According to the structure of the present invention, the difference between the thermal expansion coefficient of the window glass plate that closes the window portion of the housing member and the solder that fixes the window glass plate to the housing member can be used to prevent damage to the window. cracks in the glass pane.

Description of drawings

FIG. 1 is a perspective view showing an optical device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing components of the optical device shown in FIG. 1 .

FIG. 3 is an exploded perspective view showing the positional relationship between components of the optical device shown in FIG. 1 .

Fig. 4 is a sectional view taken along the line A-A of Fig. 3 .

(a) in FIG. 5 is a longitudinal sectional view showing an example of the positional relationship between the protrusion of the cover member shown in FIG. 4, the metallized film of the window glass plate, and the solder layer. (b) is a plan view of the portion shown in (a) in FIG. 5 .

(a) in FIG. 6 is a longitudinal sectional view showing another example of the positional relationship between the protruding portion of the cover member shown in FIG. 4, the metallized film of the window glass plate, and the solder layer. (b) is a plan view of a part shown in (a) in FIG. 6 .

(a) in FIG. 7 is a top view of the window glass plate shown in FIG. 4, and (b) in FIG. 7 shows the solder used in the formation of the solder layer shown in FIG. In the top view of the frame, (c) in FIG. 7 is a longitudinal sectional view showing the state of the solder frame disposed between the cover member and the window glass plate shown in FIG. 4 , and (d) in FIG. 7 ) is a longitudinal sectional view showing a state in which the cover member and the window glass plate are bonded by a solder layer formed of the solder frame shown in (c) of FIG. 7 .

(a) in FIG. 8 shows the light transmittance to the window glass plate in the process of fixing the window glass plate to the cover member with a solder layer when manufacturing the optical device shown in FIG. 1 . A description of the state in which a tensile load is applied to the base material. (b) in FIG. 8 is an explanatory diagram showing an example of the thermal expansion coefficient of each portion shown in (a) in FIG. 8 .

FIG. 9 is a comparative example with respect to the structure of (a) in FIG. Description of the state where the above-mentioned tensile load is applied to the light-transmitting base material of the window glass plate when the metal film is uniform in the width direction.

10 is a diagram showing an example of a main part of a conventional optical device in which an optical element is provided inside, and a window as an opening is formed in a frame constituting a case, and the window is blocked by a window glass plate. stereogram.

(a) in FIG. 11 is a sectional view taken along the line D-D in FIG. 10 . (b) in FIG. 11 is a cross-sectional view showing a state where a crack has occurred in the glass member shown in (a) in FIG. 11 . (c) in FIG. 11 is a plan view of a part shown in (b) in FIG. 11 .

detailed description

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a perspective view showing an optical device 1 according to an embodiment of the present invention. The optical device 1 of the present embodiment is an airtight LCOS package including, for example, LCOS (Liquid Crystal On Silicon: liquid crystal on silicon) as the optical element 12 .

(Appearance and function of optical device 1)

As shown in FIG. 1 , an optical device 1 is provided with an optical element 12 on a ceramic substrate 11, and light is incident from a window portion 16a of a cover member (casing member, metal frame) 16 sealing the optical element 12 and passes through the optical element 12. reflection. In this case, a diffraction grating is formed in the optical element 12 using a liquid crystal layer, and the voltage applied to the optical element 12 is changed to change the diffraction grating and further change the reflection angle of light. Specifically, when the wavelength-multiplexed light (optical signal) emitted from the optical fiber is collimated and incident on the optical element 12, the reflection angle is controlled by the optical element 12 for each wavelength, so that the reflected Light enters a plurality of optical fibers corresponding to the respective wavelength channels.

(Structure of Optical Device 1)

FIG. 2 is an exploded perspective view showing components of the optical device 1 shown in FIG. 1 . FIG. 3 is an exploded perspective view showing the positional relationship between components of the optical device 1 shown in FIG. 1 . Fig. 4 is a sectional view taken along the line A-A in Fig. 3 .

As shown in FIGS. 2 to 4 , the optical device 1 includes a ceramic substrate 11 , an optical element 12 , a heater 13 , a window glass plate (sealing glass) 15 , and a cover member (casing member) 16 .

The ceramic substrate 11 is made of, for example, alumina ceramics, and has a concave portion 11 a on the upper surface for disposing the optical element 12 .

The optical element 12 includes a silicon substrate 12a and a liquid crystal layer 12b. A diffraction grating is formed on the liquid crystal layer 12b, and the diffraction grating changes when the applied voltage changes, so that the reflection angle of incident light changes. The heater 13 includes a heating circuit (not shown) and a temperature control circuit (not shown) made of alumina ceramic material, and is provided on the lower surface of the optical element 12 . The optical element 12 and heater 13 are connected to connection terminals (not shown) by, for example, wire bonding, and the connection terminals are connected to electronic components (not shown) such as capacitors and connectors provided outside the optical device 1 .

The optical element 12 is fixed to the concave portion 11 a of the ceramic substrate 11 by the resin layer 18 . The resin layer 18 is made of, for example, a low outgassing two-component epoxy resin.

The cover member 16 has an outer peripheral portion 16b, a protruding portion 16c, and a sealing frame portion 16d, and is provided on the ceramic substrate 11 . The protruding portion 16c is formed in a state protruding upward by one stage at the inner portion of the outer peripheral portion 16b. The said window part 16a is opened in the protrusion part 16c. The sealing frame portion 16d is formed in a rectangular frame shape below the outer peripheral portion 16b. The sealing frame portion 16 d is located on the ceramic substrate 11 so as to surround the concave portion 11 a of the ceramic substrate 11 .

The cover member 16 is formed of, for example, Kovar (registered trademark) alloy which is an alloy in which nickel and cobalt are mixed with iron. The thermal expansion coefficient of Kovar (registered trademark) alloy is also low among metals around normal temperature, and has properties close to that of hard glass.

The window glass plate 15 has a translucent base material 15 a made of, for example, Kovar (registered trademark) glass. The selection of the translucent base material 15 a needs to consider the polarization dependence of the optical element 12 . That is, if the translucent substrate 15a has crystal axes like a single crystal member, the effect of a polarizing plate will be produced, so it is necessary that the angle formed by the polarization direction of the signal and the crystal axes be as consistent as possible. Therefore, it is preferable to use an amorphous (amorphous, glass-like) member for the translucent base material 15a.

An antireflection film 15b is provided on the lower surface of the translucent substrate 15a, and an antireflection film 15c and a metallized film 15d are provided on the upper surface. The antireflection film 15 b is provided on the entire lower surface of the translucent substrate 15 a , and the antireflection film 15 c is provided on the surface other than the outer peripheral portion of the window glass plate 15 . The gap between the metallized film 15d and the antireflection film 15c is, for example, 0 to 2 mm.

The metallized film 15d is provided in a ring shape on the outer periphery of the window glass plate 15, and has, for example, a chromium layer, a nickel layer, and a gold layer (Cr layer/Ni layer/Au layer) stacked in this order from the side of the light-transmitting base material 15a. ) or a two-layer structure in which a chromium layer and a gold layer (Cr layer/Au layer) are sequentially laminated. The width of the metallized film 15d affects the connection strength between the window glass plate 15 and the cover member 16, and is, for example, 0.4 mm to 1.0 mm. The metallized film 15d is provided in an annular shape, so that the solder layer 17 wetted and diffused on the metallized film 15d is also in an annular shape.

Between the upper surface of the metallized film 15d in the window glass plate 15 and the lower surface of the protruding portion 16c of the cover member 16 surrounding the window portion 16a, a solder layer 17 is provided in an annular shape. The solder layer 17 is used to join the cover member 16 and the window glass plate 15 . The solder layer 17 is made of, for example, an alloy of gold and tin (Au—Sn).

In the optical device 1, as described above, with respect to the external space of the optical device 1, the internal space of the optical device 1 surrounded by the ceramic substrate 11, the cover member 16, the solder layer 17, and the window glass plate 15 is closed. seal. Therefore, the optical element 12 present in the internal space of the optical device 1 is in a sealed state. In addition, the internal space of the optical device 1 is filled with at least one gas of helium and nitrogen at a positive pressure compared to the external pressure.

(a) in FIG. 5 is a longitudinal sectional view showing an example of the positional relationship between the protruding portion 16c of the cover member 16, the metallized film 15d of the window glass plate 15, and the solder layer 17 shown in FIG. , (b) in FIG. 5 is a plan view of the part shown in (a) in FIG. 5 . (a) in FIG. 6 is a longitudinal sectional view showing another example of the positional relationship between the protruding portion 16c of the cover member 16, the metallized film 15d of the window glass plate 15, and the solder layer 17 shown in FIG. , (b) in FIG. 6 is a plan view of the part shown in (a) in FIG. 6 .

As shown in (a) and (b) of FIG. The center of the window portion 16a of the cover member 16 recedes in the opposite direction. Therefore, the cover member 16 has the protrusion part 16c2 which is a part which protrudes toward the center direction of the window part 16a of the cover member 16 rather than the inner peripheral edge part 15d1 of the metallization film 15d.

And, as shown in (a) and (b) in FIG. The edge portion 15 a 1 recedes toward the center of the window portion 16 a of the cover member 16 . In addition, the outer peripheral side edge part 15d2 of the metallization film 15d may be the same position (coplanar) as the outer peripheral side edge part 15a1 of the translucent base material 15a.

In the example of (a) and (b) in FIG. same location. On the other hand, the outer peripheral edge portion 17b of the solder layer 17 protrudes in a direction opposite to the central direction of the window portion 16a with respect to the outer peripheral edge portion 15a1 of the translucent base material 15a.

In the example of (a) and (b) in FIG. The examples of a) and (b) are the same. However, in the examples of (a) and (b) in FIG. The center direction of the window part 16a of the cover member 16 protrudes.

(Manufacturing method of optical device 1)

Based on the above configuration, a method of manufacturing the optical device 1 will be described below. (a) in FIG. 7 is a plan view of the window glass plate 15 shown in FIG. 4, and (b) in FIG. 7 shows the solder used in the formation of the solder layer 17 shown in FIG. The top view of the solder frame 17p, (c) in FIG. d) is a longitudinal sectional view showing a state in which the lid member 16 and the window glass plate 15 are bonded via the solder layer 17 formed of the solder frame 17p.

When manufacturing the optical device 1, the cover member 16, the window glass plate 15 (see (a) in FIG. 7 ), and the solder frame 17p for bonding the cover member 16 and the window glass plate 15 are prepared. (refer to (b) in FIG. 7 ), a ceramic substrate 11 , an optical element 12 , and a heater 13 . The heater 13 is attached in advance to the lower surface of the optical element 12 with an adhesive.

As shown in (b) of FIG. 7, the solder frame 17p has a rectangular frame shape. The size of the solder frame 17p corresponds to the size of the metallized film 15d of the window glass plate 15, and is formed to have substantially the same size as the metallized film 15d. The solder frame 17p is cut and formed, for example, by releasing a plate-like solder.

In the manufacturing process of the optical device 1 , first, the cover member 16 is bonded to the window glass plate 15 . In this step, as shown in (c) of FIG. 7 , a solder frame 17p is disposed on the metallized film 15d of the window glass plate 15, and a cover member 16 is disposed thereon.

Next, in the state of (c) in FIG. 7 , the cover member 16, the window glass plate 15, and the solder frame 17p are heated to the melting temperature of the solder frame 17p. This step is performed by, for example, reflow soldering. The heating in this case is performed under normal pressure and under an atmosphere of air or nitrogen.

After that, the melting of the solder frame body 17p continues, and the metallized film 15d of the window glass plate 15 and the lower surface of the cover member 16 are wetted by the solder of the solder frame body 17p. In the state, as shown in (d) of FIG.

Next, on the concave portion 11 a of the ceramic substrate 11 , the optical element 12 and the heater 13 integrated by bonding are fixed with the resin layer 18 .

Finally, the cover member 16 to which the window glass plate 15 is bonded is brazed to the ceramic substrate 11 under normal pressure and in an atmosphere of at least one of helium and nitrogen.

(Advantages of Optical Device 1)

(a) in FIG. 8 shows the light transmittance to the window glass plate 15 in the process of fixing the window glass plate 15 to the cover member 16 by using the solder layer 17 when the optical device 1 is manufactured. Explanation of a state where a tensile load is applied to the base material 15a. (b) in FIG. 8 is an explanatory diagram showing an example of the thermal expansion coefficient of each portion shown in (a) in FIG. 8 . FIG. 9 is a comparative example with respect to the structure of (a) in FIG. 8, and shows that the position of the window side edge portion 16c1 of the cover member 16 and the position of the inner peripheral side edge portion 15d1 of the metallized film 15d are in the same position. A state in which the above-mentioned tensile load is applied to the light-transmitting base material 15a of the window glass plate 15 when the metallized film 15d is uniform in the width direction will be described.

Fixing the window glass plate 15 to the cover member 16 by melting the solder frame 17p serving as the solder layer 17 between the cover member 16 and the metallized film 15d of the window glass plate 15 In this case, the molten solder of the solder frame 17p is cooled and shrunk. In this case, since the thermal expansion coefficient of soldering is larger than the thermal expansion coefficient of the light-transmitting base material 15a of the window glass plate 15, as shown in (a) in FIG. The difference in thermal expansion coefficient of the light-transmitting base material 15a applies a tensile load (tensile stress) indicated by an arrow to the light-transmitting base material 15a.

Here, the molten solder also adheres to the protruding portion 16c2 of the cover member 16, so that the protruding portion 16c2 suppresses the movement of the solder of the solder layer 17 in the width direction (the direction of the metallized film 15d). width direction) toward the center direction, thereby slowing down the tensile load applied to the light-transmitting base material 15a. Thereby, it is possible to prevent cracks from being generated in the translucent base material 15a.

On the other hand, when the position of the window-side edge portion 16c1 of the cover member 16 matches the position of the inner peripheral edge portion 15d1 of the metallized film 15d in the width direction of the metallized film 15d, the cover The part 16 does not have the protruding portion 16c2, so the function of suppressing the shrinkage of the solder of the solder layer 17 toward the center direction in the width direction is reduced. Therefore, in the structure shown in FIG. 9 , compared with the structure shown in FIG. 8( a ), the function of preventing cracks from being generated in the translucent base material 15 a is lowered.

In addition, in the optical device 1, since the cover member 16 has the protruding portion 16c2, the solder material layer 17 formed by the solder material wetted and diffused on the metallized film 15d of the window glass plate 15 is located near the window. The end portion on the side of the portion 16a is less likely to project into the window portion 16a (difficult to protrude). Accordingly, the solder layer 17 can prevent the opening area of the window portion 16 a from being narrowed. That is, since the opening area of the window portion 16 a is enlarged, it is possible to prevent the lid member 16 , that is, the optical device 1 from being enlarged.

In addition, in the optical device 1, the cover member 16 is formed of Kovar (registered trademark) alloy, and the light-transmitting base material 15a is formed of Kovar (registered trademark) glass, so that the cover member 16 and the light-transmitting base material 15a The thermal expansion coefficients are substantially equal, and the thermal expansion coefficient of the cover member 16 is smaller than that of the solder layer 17 . Therefore, the cover member 16 cannot shrink together with the solder when the solder in the solder layer 17 is cooled, but the cover member 16 having the protruding portion 16c2 can reliably prevent the light-transmitting base material 15a from shrinking. cracks in.

Here, the relationship between the thermal expansion coefficients of the cover member 16, the translucent base material 15a of the window glass plate 15, and the solder layer 17 is preferably such that the thermal expansion coefficient of the cover member 16 and the translucent base material 15a are The thermal expansion coefficients are equal, and the thermal expansion coefficient of the cover member 16 is smaller than that of the solder layer 17 .

As shown in (b) in FIG. 8, the coefficient of thermal expansion of each part shown in (a) in FIG. (Kovar (registered trademark) glass) was 5.0 ppm/K, and the solder layer 17 (Au—Sn solder) was 16.2 ppm/K.

In addition, the preferred combination of the material of the cover member 16 and the material of the translucent substrate 15a is excluding the combination in which the cover member 16 is Kovar (registered trademark) alloy and the translucent substrate 15a is Kovar (registered trademark) glass. Besides, the following combinations are also possible. For example, a combination of the lid member 16 (platinum): 8.8 ppm/K and the translucent base material 15 a (lead glass): 8.4 to 9.1 ppm/K may be used. Or the combination of the cover member 16 (tungsten): 4.5 ppm/K and the translucent substrate 15 a (borosilicate glass): 4.3 to 4.6 ppm/K or (aluminosilicate glass) 4.2 to 4.6 ppm/K. Or the combination of the cover member 16 (carbon steel): 10.8 ppm/K and the translucent base material 15 a (lead glass): 10.4 ppm/K, or the like.

〔Summarize〕

The optical device according to this embodiment includes: a casing member having an opening window; an optical element provided inside the casing member, and light is incident on the optical element through the window; and a window glass plate, It is installed so as to close the above-mentioned window part, and in this optical device, the above-mentioned window part glass plate has a light-transmitting base material and a metal-clad film, and the metal-clad film is formed on the above-mentioned light-transmitting base material with a predetermined width. The outer peripheral part of the above-mentioned window part glass plate is fixed to the above-mentioned case part by the solder layer provided between the above-mentioned metallized film and the above-mentioned case part, and the side of the above-mentioned case part near the above-mentioned window part The edge portion has a protruding portion that protrudes toward the center of the window portion than the edge portion on the inner peripheral side of the metallized film.

According to the above configuration, in the manufacture of the optical device, the window glass plate is fixed by melting the solder as the solder layer between the case member and the metallized film of the window glass plate. In the case of housing components, the molten solder is cooled and shrinks. In this case, the thermal expansion coefficient of the solder is larger than the thermal expansion coefficient of the light-transmitting base material of the window glass plate, so the difference between the thermal expansion coefficient of the solder and the thermal expansion coefficient of the light-transmitting base material A tensile load (tensile stress) is applied to the translucent substrate. However, the molten solder also adheres to the protruding portion of the case member, so the protruding portion suppresses the shrinkage of the solder of the solder layer toward the center in the width direction, thereby relieving The tensile load applied to the light-transmitting substrate. Thereby, it is possible to prevent cracks from being generated in the translucent base material.

In addition, since the case member has an overhanging portion, the end portion of the solder layer on the side of the window portion formed by the solder material wetted and diffused on the metallized film of the window glass plate is less likely to protrude into the window portion. (not easy to stick out). Accordingly, it is possible to prevent the opening area of the window portion from being narrowed by the solder layer.

In the above-mentioned optical device, the above-mentioned casing member may be constituted by a metal frame, the above-mentioned window glass plate is a sealing glass having a thermal expansion coefficient corresponding to the above-mentioned metal frame, and the thermal expansion of the above-mentioned solder layer The coefficient is larger than the thermal expansion coefficient of the housing member and the window glass plate.

According to the above structure, the housing member is made of a metal frame, the window glass plate is sealing glass having a thermal expansion coefficient corresponding to that of the metal frame (the thermal expansion coefficient is approximately equal to the metal frame), and the thermal expansion coefficient of the solder layer is higher than that of the housing member and the metal frame. The thermal expansion coefficient of the window pane is large. Therefore, in the manufacturing process of the optical device, when the solder material as the solder material layer is melted to fix the window glass plate to the case member with the solder material, the case member is The solder layer's solder does not shrink with the solder when it cools. As a result, the function of preventing cracks from occurring in the window pane due to the case member having the overhanging portion can be reliably obtained.

In the above optical device, the casing member may be made of Kovar (registered trademark) alloy, and the translucent base material of the window glass plate may be made of Kovar (registered trademark) glass.

According to the above configuration, Kovar (registered trademark) alloy is used for the case member, and Kovar (registered trademark) glass is used for the light-transmitting base material of the window glass plate, so that the thermal expansion coefficient of the case member and The coefficients of thermal expansion of the window panes are approximately equal. In this way, the function of preventing cracks from occurring in the window pane due to the housing member having the overhang can be further reliably obtained.

In the above-mentioned optical device, a dimension of the protruding portion in the width direction of the metallized film may be 0.2 mm to 0.5 mm.

According to the above configuration, the size of the projecting portion of the housing member in the width direction of the metallized film is 0.2 mm to 0.5 mm, so that the size of the optical device can be prevented, and the projecting portion can be reliably formed. The protruding portion is used to prevent cracks from being generated in the window pane.

That is, when the dimension of the overhang in the width direction of the metallized film is less than 0.2 mm, the overhang may not be formed due to tolerances when assembling the optical device by hand, for example. On the other hand, if the above dimension is set to be 0.2 mm or more, the overhanging portion can be reliably formed.

In addition, when the dimension of the projecting portion in the width direction of the metallized film is larger than 0.5 mm, the window portion becomes narrow. In order to avoid this situation, the optical device needs to be enlarged, and in this case, the size of the optical device will be increased. Therefore, by setting the above-mentioned size to 0.5 mm or less, it is possible to prevent an increase in the size of the optical device.

The present invention is not limited to the above-mentioned embodiments, and various changes can be made within the range indicated by the technical solutions. Embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the present invention. within the technical range.

The present invention can be used as a switch for switching the optical path of light.

Explanation of reference signs

1...optical device; 11...ceramic substrate; 12...optical element; 13...heater; 15...window glass plate; 15a...light-transmitting substrate; 15b...anti-reflection film; Metallized film; 15d1...inner peripheral edge; 15d2...outer peripheral edge; 16...cover member (casing member); 16a...window; 16b...outer peripheral; 16c...protrusion; 16c1...window 16c2...extending part; 17...solder layer; 17a...inner peripheral edge; 17b...outer peripheral edge; 17p...solder frame; 18...resin layer.

Claims (4)

1. An optical device comprising: a housing part having an open window; an optical element provided inside the case member, and light is incident on the optical element through the window; and a window glass plate arranged to block said window, The optical device is characterized in that, The window glass plate has a light-transmitting base material and a metallized film formed on the outer periphery of the light-transmitting base material with a predetermined width, The window glass plate is fixed to the housing member with a solder layer provided between the metallized film and the housing member, The end edge portion of the housing member on the side of the window portion has a protruding portion, and the protruding portion is more toward the center of the window portion than the end edge portion on the inner peripheral side of the metallized film. highlighted part. 2. The optical device according to claim 1, characterized in that, The housing part consists of a metal frame, The window glass plate is sealing glass having a coefficient of thermal expansion corresponding to that of the metal frame, The thermal expansion coefficient of the solder layer is larger than the thermal expansion coefficients of the case member and the window glass plate. 3. The optical device according to claim 2, characterized in that, The housing part is made of Kovar (registered trademark) alloy, The translucent base material of the window glass plate is made of Kovar (registered trademark) glass. 4. Optical device according to any one of claims 1 to 3, characterized in that A dimension of the protruding portion in the width direction of the metallized film is not less than 0.2 mm and not more than 0.5 mm.